Kalgoorlieite is an extremely rare telluride mineral discovered in the famous gold-mining district of Kalgoorlie, Australia. It occurs primarily as tiny metallic grains intergrown with other telluride minerals and gold in hydrothermal vein systems. Due to its scarcity and small grain size, it is primarily a target for specialized mineralogists and advanced systematic collectors.

Hardness

2-3

Mohs

Luster

Metallic

Streak

Gray

Transparency

Opaque

mineralrare

Kalgoorlieite

Hardness: 2-3
Luster: Metallic
Streak: Gray
Transparency: Opaque

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Is this kalgoorlieite?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch kalgoorlieite with a known reference. Kalgoorlieite sits at Mohs 2-3 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Kalgoorlieite leaves a gray streak.
3
Read the luster
Hold the specimen under a strong light. Kalgoorlieite typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: white, gray.
5
Look at form & habit
Crystal system: hexagonal. Typical habit: anhedral grains.

Often confused with

Kalgoorlieite vs. its common look-alikes — and how to tell them apart in the field.

mineral

Altaite

Mohs 2.5-3

How to tell apart: Streak differs — Kalgoorlieite leaves gray, Altaite leaves black.

How to tell apart: Streak differs — Kalgoorlieite leaves gray, Coloradoite leaves black.

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Often found alongside kalgoorlieite

Minerals reported to co-occur with kalgoorlieite. Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula: TeAs₂
Mohs hardness: 2-3
Density: 8.8-9.0 g/cm³
Colors: White Gray
Streak: Gray
Luster: Metallic
Transparency: Opaque
Crystal system: Hexagonal
Crystal habit: Anhedral Grains
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Gold-telluride Veins
Typical price: $100-500 per specimen

Where rockhounds find kalgoorlieite

Classic worldwide localities

Kalgoorlie-Boulder, Western Australia

Field-hunting tip

Look in hydrothermal gold-telluride veins country — that is the host setting where kalgoorlieite typically forms. If you start seeing gold, altaite, pyrite in float, you are in the right ground. Field specimens usually show a anhedral grains habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify kalgoorlieite?+

Mohs hardness is 2-3. It typically shows a metallic luster. The streak is gray. Common colors include white, gray.

Where is kalgoorlieite found?+

Notable localities include Kalgoorlie-Boulder, Western Australia.

How much is kalgoorlieite worth?+

Typical asking prices fall in the range of $100-500 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

Is kalgoorlieite safe to handle?+

It contains toxic constituents. Contains arsenic and tellurium, both of which are toxic. Handle with care, wash hands after handling, and avoid inhaling dust. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like kalgoorlieite?+

Kalgoorlieite is most often confused with Altaite, Coloradoite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with kalgoorlieite?+

Kalgoorlieite commonly co-occurs with Gold, Altaite, Pyrite, Quartz. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does kalgoorlieite form in?+

Kalgoorlieite typically forms in hydrothermal gold-telluride veins. Working float back to the host body is the standard way to chase a fresh occurrence.

What is kalgoorlieite used for?+

Kalgoorlieite is used in collector.

Find kalgoorlieite on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.